def test_subterms(self):
"""A Variable supports iterating its subterms."""
x = Variable(name='x')
expected_subterm_set = {((), x)}
actual_subterm_set = set(x.subterms())
self.assertEqual(expected_subterm_set, actual_subterm_set)
def test_positions(self):
"""A Variable supports iterating its positions."""
x = Variable(name='x')
expected_position_set = {()}
actual_position_set = set(x.positions())
self.assertEqual(expected_position_set, actual_position_set)
def test_call(self):
"""A Function symbol can be called to create a Term."""
f = Function(name='f', arity=2)
x = Variable(name='x')
y = Variable(name='y')
term = f(x, y)
self.assertIsInstance(term, Term)
def setUp(self) -> None:
"""Set up useful stuff for testing."""
self.f = Function('f', 2)
self.g = Function('g', 1)
self.a = Constant('a')
self.b = Constant('b')
self.c = Constant('c')
self.x = Variable('x')
self.y = Variable('y')
self.z = Variable('z')
def setUp(self):
"""Set up useful stuff for testing."""
self.f = Function('f', 2)
self.g = Function('g', 1)
self.x = Variable('x')
self.y = Variable('y')
self.z = Variable('z')
self.g_subterm = Term(root=self.g, children=(self.x, ))
self.f_subterm = Term(root=self.f, children=(self.y, self.z))
self.term = Term(root=self.f,
children=(self.g_subterm, self.f_subterm))
def test_variables(self):
"""A Variable supports iterating its variables."""
x = Variable(name='x')
expected_variables = {x}
actual_variables = set(variables(x))
self.assertEqual(expected_variables, actual_variables)
def test_fresh_throws(self):
"""The fresh_variable function throws for non-pool objects.
For variables that were not generated by a VariablePool, and for other
random objects, fresh_variable should raise a ValueError.
"""
x = Variable('x')
y1 = IndexedVariable('y', 1)
z = 5
with self.assertRaises(ValueError):
fresh_variable(x)
with self.assertRaises(ValueError):
fresh_variable(y1)
with self.assertRaises(ValueError):
fresh_variable(z)
def test_getitem_invalid(self):
"""A Variable has no non-root position."""
x = Variable(name='x')
with self.assertRaises(KeyError):
x[(0, )]
def test_getitem_root(self):
"""A Variable is its own root subterm."""
x = Variable(name='x')
self.assertIs(x[()], x)
def test_str(self):
"""A Variable formats as a string."""
x = Variable(name='x')
self.assertEqual(str(x), '?x')